Automatic packaging machine having quickly replacable mandrels

ABSTRACT

A mandrel for an automatic packaging machine enables a loading of product when a great precision is required or when the characteristics of a product will not tolerate mandrels with a plurality of separate parts. The mandrel is machined with great precision from a block of metal. A conveyor on the automatic packaging machine carries a plurality of mandrels around a closed path. To enable an exchange between different types of mandrels, an air cylinder controlled quick coupler enables an installation of the mandrel on and a release of the mandrel from the conveyor. The quick coupler is a stud on the bottom of each mandrel and a slide at each location on the conveyor where a mandrel is carried. The slide has a keyhole with a large end which allows the stud to pass into and out of the keyhole and be released from the packaging machine. The stud is captured in the small end of the keyhole. Preferably, robot changes the mandrels under control of a computer; however, the mandrels may also be replaced by a manually operated or release structure.

[0001] This is a formal application replacing provisional application Serial No. 60/231,107 filed Sep. 8, 2000.

[0002] This invention relates to automatic packaging machines having replaceable mandrels and more particularly to machines having replaceable mandrels of different types and widths for inserting products into containers, with extreme accuracy.

[0003] In an automatic packaging machine, a mandrel is a mechanical structure, a plurality of which are carried around a closed conveyor path, usually carried by an endless link chain trained over sprocket wheels. The mandrel receives product, a container, etc. and carries it around the closed path to a terminal point by which time it has been packaged. At fixed locations along the conveyor path, the mandrel is presented to different work stations. For example, the mandrel may pick up a carton at a first work station, receive product in the carton at the next work station, seal the carton at a third work station, and discharge the sealed carton at a fourth work station. Since most automatic packaging machines are used to package many different products, many mandrels having many different physical configurations are desired. For example, one configuration may be adapted to load golf balls, another to load candy, another to load food to be frozen, etc.

[0004] One mandrel which has proven to be very useful has a variable width tray (U.S. Pat. No. 5,072,753). For example, a product such as a pouch or bag of loose peas must be shaped into a generally rectangular configuration conforming to the interior dimensions of a frozen food box and then inserted into the box. On the way to the box, some pouched products must be “conditioned” by being repeatedly squeezed gently, relaxed, and squeezed again. The variable width mandrel of U.S. Pat. No. 5,072,753 serves this purpose admirably.

[0005] On the other hand, other products require greater precision in loading. For example, some products must be inserted into a carton having internal dimensions providing a clearance in the order of only 35-thousandths of an inch larger than the external dimensions of the product. For this demanded precision, the variable width tray of U.S. Pat. No. 5,072,753 is not adequate. Of course, a precisely dimensioned mandrel may insert a smaller product into a carton where there is more than 35 thousandths clearance.

[0006] Spaghetti provides another example of a need for a mandrel which replaces the variable width tray of U.S. Pat. No. 5,072,753. For example, a spaghetti business sells its products in, say, five different size boxes ranging from 5½″×2¾″ to 2¾″×1⅜″. Therefore, the owner must either change the dimensions of his mandrels or buy five different automatic packaging machines, which would be both prohibitively expensive and completely impractical. However, the variable width mandrels are not a practical way of loading some other products. In the example of spaghetti, there are many thin, string-like noodles which may become lodged in and wedged between the parts of the variable width trays. Still, there is a need to shape a bundle of spaghetti noodles to fit into a box having a rectangular interior cross section, if a full weight is to be insured for each box regardless of its size. A moment's reflection will quickly bring to mind many other examples of a need to provide a variety of different size mandrels capable of accommodating different products and to load under conditions of extremely tight tolerances.

[0007] If the variable width tray is not used, the conventional procedure is to stop the automatic packaging machine and manually replace each mandrel with a different mandrel, which is a labor intensive task. That is an expensive and time consuming procedure. The greatest expense is the down time of the automatic packing machine while no product is being loaded.

[0008] Accordingly, there is a need for an automatic packaging machine where mandrels may be quickly and easily removed and replaced, preferably automatically under the control of a computer.

[0009] An object of the invention is to provide mandrels which can load product with great precision. Here an object is to provide means for making a quick change of mandrels mounted on an automatic packaging machine so that different products having different configurations may be accommodated by many different types or sizes of mandrels. In particular, an object is to provide means for automatically confirming that the correct mandrels have been installed after a quick change of mandrels has been completed.

[0010] Yet another object of the invention is to provide mandrels capable of loading products which do not lend themselves to loading by conventional means. In particular, an object is to load product having physical characteristics which might clog, or otherwise render more conventional mandrels inoperative.

[0011] In keeping with an aspect of the invention, these and other objects are accomplished by providing precisely machined mandrels in a variety of different types and sizes. The machined mandrel is shaped to guide and direct product into a proper position, to fit adjacent a box or cartridge with an extremely tight tolerance, and to enable the product to be shaped while in the mandrel.

[0012] The mandrels are quickly installed on or released from a conveyor by a combination of a stud depending from each mandrel and a slide plate having a keyhole-shaped slot therein. One of the slide plates is at each location where a mandrel is to be carried by the conveyor. The plate automatically moves between a first position which enables the stud on the mandrel to be inserted into or to escape through a large end of the keyhole slot and a second position where the stud is captured in the small end of the keyhole slot. A light reflective member is provided on each of the mandrels to identify its type. After the mandrels are installed, the conveyor is moved through one complete cycle. The reflective member on each mandrel passes a photoelectric cell which reads the mandrel type. If the reading indicates that an improper type mandrel has been installed on the conveyor, the packaging machine stops until the improper mandrel has been replaced with a correct one.

[0013] The invention will be best understood from the following specification, taken with the attached drawings, in which:

[0014]FIG. 1 schematically shows an automatic packaging machine with a few exemplary mandrels installed thereon;

[0015]FIG. 2 is a perspective view of five of the mandrels with a quick connect/disconnect mechanism for capturing or releasing the mandrels;

[0016]FIG. 3 is a side elevation of the equipment shown in FIG. 2;

[0017]FIG. 4 is an exploded view, in side elevation, of a mandrel and the quick connect/disconnect mechanism;

[0018]FIG. 5 is a perspective view of the equipment that is also shown in FIG. 4;

[0019]FIG. 6 is a plan view of a slide having a keyhole slot, which is part of the quick connect mechanism;

[0020]FIG. 7 is a side elevation of the slide shown in FIG. 6; and

[0021]FIG. 8 schematically shows a robot for automatically changing mandrels, preferably under the control of a computer.

[0022]FIG. 1 illustrates those parts of an automatic packaging machine 18 which give the information required to understand the invention. Briefly a metal frame is shown with a conveyor for moving a plurality of mandrels 20 along a closed path. If more detailed information is desired, please see the inventor's other patents on automatic packaging machines, a few of which are U.S. Pat. Nos. 5,058,634; 5,072,573; 5,185,984; 5,388,389; and 5,452,568. U.S. Pat. No. 5,072,753 shows a variable width tray designed to change its width in order to shape a bag and then to insert it into a carton. This patent discloses an excellent mandrel enjoying a wide use; however, it is not adapted to fit product into tight places with an extremely small clearance and sometimes product may become wedged between overlapping halves of the tray.

[0023]FIG. 1 is perspective view of an exemplary number of inventive mandrels 20 mounted on a conveyor of an automatic packaging machine. For identification purposes, one mandrel is shown at 22. A pneumatic or air cylinder 24 pushes or retracts a reset plate 26. Endless link chains at 28, 29 convey these and other mandrels 20 over a closed path 27 through the packaging machine. A photosensor 30 monitors the passage of each mandrel as the conveyor carries the mandrels in the direction 27. The photosensor 30 measures the width of or another index on each mandrel in order to confirm that each of the newly installed mandrels is the correct type of mandrel. If photosensor 30 detects an incorrect width or other index, the conveyor stops until a proper and correct mandrel replaces the incorrect one.

[0024] Means are provided for quickly and easily releasing or capturing a group of mandrels. In greater detail, FIG. 2 shows a group of five mandrels 20, including the one identified at 22. Each mandrel is a single block of metal which has been machined to provide a box-like structure with an open top and ends for providing a pocket for receiving product. The box-like structure has precise interior and exterior dimensions for receiving product and inserting it into a tight space with close tolerance.

[0025] The top walls of the box-like structure are tapered, as shown at 32, to guide and direct product falling into the open space. Paired open slots (one matched pair of which is shown at 34, 34) are provided on the opposite sides of the pocket or box-like structures to receive a pressing member 35 (FIG. 4) which may be lowered into the pocket via the pair of slots 34, 34 in order to shape the product or to insure that product is flat on the floor of the box. For example, if the product is spaghetti, the pressing member will positively form a bundle of the noodles into an aggregation having a generally rectangular cross section that fits into a carton.

[0026] A preferably white nylon block 36 (FIG. 2) having a width A is a pusher which travels in direction B to push product from the interior space of the mandrel into the open end 39 of a confronting carton (shown at 40 in FIG. 1) which is in a position before mandrel for receiving the product. The preferred block 36 is white to reflect light in order to facilitate the sensor 30 reading the width of the mandrel, although other suitable indicia such as a bar code may also be provided. The code is especially attractive when different types of mandrels having the same width are used.

[0027] More particularly, the pusher block 36 (FIG. 2) rides on side rails 41, 41 as it slides in Direction B. Since the side rails are on the interior vertical walls of the mandrel, the block 36 is as wide as the mandrel. Therefore, if a mandrel with an incorrect width is installed, the pusher block will have a non-standard width for the newly installed mandrel.

[0028] After all of the newly installed mandrels are in place, the conveyor is operated through one complete cycle. A sensor 30 reads the width of each of the mandrels as they are presented to the sensor. If sensor 30 reads any width other than the width A, the conveyor stops and the incorrect mandrel is replaced by a correct mandrel. If the mandrel has a type of identification characteristic other than width, the sensor reads another identification symbol at 36, such as a bar code, for example. Accordingly, after the conveyor has traveled through one complete cycle, every mandrel will have been presented to sensor 30, generating a confirmation of the correctness of the installed mandrels.

[0029] Normally, the air cylinder 24 is in a retracted position and plate 26 is as far away from the mandrels 20 as it can be. When the air cylinder 24 operates, plate 26 slides forward (Direction C) on tracks 43, 43, as far as it can go. The plate 26 is connected to and moves bar 38, which is seen in FIG. 2 at 38A, 38B, and 38C. In turn, the bar 38 pushes a slide plate 40 (FIG. 3) on a quick disconnect member 42. When the air cylinder 24 retracts, bar 38 also retracts, as does slide plate 40, which is pulled to its normal resting position by coiled spring 72.

[0030] The details of the quick disconnect member 42 are best seen in FIGS. 4 and 5. Briefly, the disconnect member 42 is fixed to a block of metal 76 riding on bars 78, 80 which are attached to and moving with the link chain conveyor at 28, 29 (FIG. 1). The quick disconnect member 42 either locks mandrel 22 in place on the conveyor chain or unlocks it for a quick change of mandrels. Disconnect member 42 can be operated in response to either a manual command signal or a computer generated signal controlled from a distant location.

[0031] In greater detail, the mandrel 22 is bolted to a plate 50 having a connector stud 52 fixed thereto and dependent therefrom. Plate 50 rests on top of a block of metal 60 and between rails 66, 68 which fix the position of plate 50. A circumferential locking groove 54 is formed on the stud. The outer end of the stud is chamfered at 56 to guide and direct the entrance of the stud into a locking keyhole 58. The block of metal 60 has a passageway 62 milled therein with a slide plate 64 having keyhole 58 sliding through the passageway 62. When plate 50 is in position on block 60, the dependent connector stud 52 passes through a hole 65 in metal block 60 and on into the large end of keyhole 58 in slide plate 40.

[0032] A pair of coiled springs 72 (FIGS. 3, 4) are coupled between block 60 and slide plate 40 to urge the slide plate in Direction D so that the small end of keyhole 58 normally enters locking groove 54 on stud 52 in order to lock the mandrel in position on the disconnect mechanism 42. When air cylinder 24 (FIGS. 2, 3) pushes plate 26 and rod 38 in Direction C, the slide plate 40 moves counter to the spring bias so that the small end of keyhole 58 leaves locking groove 54 and the dependent connector stud 52 is released via the large end of keyhole 58. At this time, mandrel 22 may be lifted off the disconnect member 42 and a different size or other type of mandrel may be installed. When air cylinder 24 returns to normal, plate 26 and bar 38 also return to normal, at which time the springs 72 pull the slide plate 40 in Direction D to capture the locking groove 54 in the small end of keyhole 58, thereby locking the new mandrel to the metal block 60.

[0033] The metal block 60 is bolted to a carrier 76 which is slidingly held in place by two parallel bars 78, 80, connected at their opposite ends to the conveyor chains at 28, 29 (FIG. 1). The carrier 76 has a slot 82 which provides a lost motion for movement of rod 78 in order to facilitate a mandrel circling a conveyor sprocket wheel, or the like, as explained in U.S. Pat. No. 5,185,984.

[0034]FIG. 6 is a plan view and FIG. 7 is a side elevation view of slide plate 40. The top of slide plate 40 is slightly tapered (here, 0.041 thousandths) toward the keyhole 58, as shown in plan view at 84 in FIG. 6 and by dashed line 84 in FIG. 7. When slide plate 40 is new, this taper stops the travel of slide plate 40 as it moves into locking groove 54 on the connector stud 52. Hence, the slide plate is moved a distance which is less than the full length of the small end of keyhole slot 58, thereby leaving a space 86 for future travel as the surface of the slide member 40 wears so that the plate slides further as the tapered part becomes thinner, in order to increase the life of the slide plate. Holes 88 are formed on the distal end of slide plate 40 in order to receive screws which anchor distal ends of coiled springs 72.

[0035]FIG. 8 shows a computer controlled robot for changing the mandrels while the slide plate 40 is in a release position for unlocking the connector stud 52 from the keyhole 58. After a new mandrel is in place, the slide plate is moved to the capture position. A computer is shown at 91 to control robot 92, as indicated by dashed line 93. The computer coordinates and moves air cylinder 24 in synchronism with robot 92.

[0036] Four mandrel storage magazines “1-4” are shown at 90. Each magazine contains mandrels of a certain individually associated size or type. Here, by way of example, it is assumed that there are four sizes of mandrels. Each magazine has an elevator conveyor circling the magazine in Direction E for carrying and presenting mandrels at a fixed position where a robot 92 can pick up or deposit a mandrel. The robot 92 travels back and forth (Directions F and G) on track 94. If, for example, the old mandrels being removed from the conveyor at 96 (FIG. 1) is the smallest mandrel, robot 92 will stop in front of magazine 1. If the new mandrels being installed are the largest, the robot 92 will stop in front of magazine 4, for example. Other sizes or types of mandrels are in magazines 2, 3. Of course, any number of magazines and mandrel sizes or types may be accommodated.

[0037] The robot 92 has an articulated arm 97 which is shown lifting mandrel 98 from space 95 on conveyor 96. This mandrel will be deposited in an empty space in magazine 1, for example. Then, the robot moves along track 94 to a selected one of the magazines 2-4 where it picks up a new mandrel having a different size or type. For example, the robot 92 might pick up mandrel 99 from magazine 3 and carry to and install it in space 95 from which mandrel 98 has just been removed. Preferably, the robot operation is carried out under the control of computer 91, although manual control of the robot may also be provided.

[0038] After all new mandrels are installed, the conveyor 96 is driven through a complete cycle where every pusher block 36 (FIGS. 1 and 2) on the conveyor is presented to sensor 30. The sensor 30 shines a light on and picks up a light reflected from pusher block 36 to measure its width A (FIG. 2). If the width of any newly installed mandrel is different from the selected standard width “A” of a desired mandrel, the conveyor stops in a position where the odd-sized mandrel can be removed and replaced.

[0039] The advantages of the invention should now be apparent. If a product has characteristics which require extreme precision for packaging or if the product has certain characteristics which defy normal handling, extremely precise one piece mandrels may be required. However, automatic packaging machines often require a flexibility which enables them to package many different products. Hence, a number of different mandrel configurations are desirable. When it is not possible or desirable to have variable mandrels, it is necessary to physically change the mandrels. However, conventionally, the cost of making such mandrel changes is very high. This invention reduces those cost while making it possible to provide a wide range of mandrel options and to enable computer control over replacement of mandrels.

[0040] Those who are skilled in the art will readily perceive various modifications and adaptations that may be made. Therefore, the appended claims are to be construed to cover all equivalents falling within the scope and spirit of the invention. 

The claimed invention is:
 1. An automatic packaging machine comprising a conveyor means carrying a plurality of mandrels around a closed path, each of said mandrels including a quick release coupler means for releasably coupling said mandrels to said conveyor means, means for normally urging said coupler means to a position for capturing a mandrel, and means associated with at least one of said captured mandrels for selectively operating said coupler means to a release position against the urging of said urging means, whereby said mandrels may be replaced quickly and easily in order to change one type of said mandrels to another type of said mandrels.
 2. The machine of claim 1 wherein said means for selectively operating said coupler is associated with a group of mandrels, and means for releasing or capturing said group of said mandrels.
 3. The machine of claim 1 wherein said coupler means comprises a coupler stud on each of said mandrels and a slide mounted on said conveyor at each location where a mandrel is carried, said stud having a locking groove thereon, said slide having a keyhole-shaped slot thereon, said stud passing through a large end of said keyhole slot when slide is in said release position, said locking groove being captured in a small end of said keyhole slot when said slide is in said capture position.
 4. The machine of claim 3 where a surface on said slide adjacent said keyhole is tapered to limit travel of said slide as said groove is captured in said small end of said keyhole, normally said taper limiting movement of said slide so that said groove is captured before it reaches the end of said keyhole when there is no wear on said slide, whereby wear on said surface increases said taper to enable said locking groove to enter further into said small end as wear increases.
 5. The machine of claim 1 and robot means for lifting a mandrel from and replacing a mandrel in a location on said conveyor while said coupler means is in said release position at said location.
 6. The machine of claim 5 and a plurality of magazines accessible to said robot means, each of said magazine means storing a plurality of mandrels of an individually associated type, and means for moving said robot means from said location to one of said magazines in order to deposit said lifted mandrel of one of said types in said one of said magazines and for moving said robot to another of said magazines in order to retrieve a replacement one of said mandrels of a different type, and means for moving said robot means to said location in order to install said replacement mandrel on said conveyor at said location.
 7. The machine of claim 6 wherein said mandrel is machined from a solid block of metal in order to form a precisely dimensioned, open-topped box structure, said box structure having top edges which are tapered to guide and direct product into said box structure.
 8. The machine of claim 7 and at least one matched pair of slots on opposite side walls of said box structure for receiving a pressing member for shaping or positioning said product for insertion into a carton.
 9. The machine of claim 1 and identification means associated with each of said mandrels for indicating a type thereof, sensor means responsive to said identification means for detecting said type of each of said mandrels, means for driving said conveyor through a complete cycle, and means responsive to said sensor means finding a non-standard mandrel for stopping said conveyor in order to replace said non-standard mandrel.
 10. The machine of claim 9 wherein each of said types is a mandrel has a different width, and said identification means is a pusher for pushing product out of said mandrel, said pusher having a width corresponding to a width of said mandrel, said sensor shining light on and reading light reflected from said pusher.
 11. An automatic packaging machine having a plurality of precisely dimensioned mandrels carried around a closed path by a conveyor, whereby said mandrels may precisely insert product into a carton within extremely small dimensional tolerance, and quick coupler means for enabling a replacement of one type of said mandrels with another type of mandrel, whereby said replacement of said mandrels provide said machine with a variety of types of mandrels, and means responsive to said replacement mandrels for confirming that all of said replacement mandrels are a correct type of mandrel.
 12. The machine of claim 11 wherein said confirming means is a means for measuring the width of each mandrel after each replacement of said mandrels, and means responsive to detection of a non-standard width of a mandrel for stopping said machine in order to facilitate a replacement of said non-standard mandrel with a standard mandrel.
 13. The machine of claim 12 wherein said width measuring means is a pusher comprising block of nylon for reflecting light to a sensor as said conveyor carries said mandrels around said closed path.
 14. The machine of claim 11 wherein said extremely small tolerance is in the order of at least 35-thousandths of an inch.
 15. A quick replacement mandrel for use on a conveyor of an automatic packaging machine, said mandrel comprising an open box-like structure having a locking stud depending from the bottom thereof, a slide member having a keyhole therein, coupler means attached to said conveyor at each location where a mandrel is carried, said coupler means defining a passageway for enabling said slide member to move back and forth, an entrance hole formed in said coupler means and over said keyhole, said entrance hole being large enough to enable said stud to enter a large end of said keyhole while said slide member is in a first position, a groove on said stud having dimensions enabling it to be captured within a small end of said keyhole when said slide is in a second position, means for normally urging said slide to said second position, means for moving said slide to said first position and against said urging of said urging means, whereby said capture of said stud is released and said mandrel may be replaced, and means for releasing said moving means whereby said urging means moves said slide to said second position for capturing the stud on said replaced mandrel.
 16. The mandrel of claim 15 where said urging means is a spring acting upon said slide and said moving means is an air cylinder.
 17. The mandrel of claim 16 wherein said urging means is a coiled spring stretched between said coupler means and said slide.
 18. The mandrel of claim 16 wherein said box-like structure is a precisely machined block of metal whereby said mandrel can load a product into a space with an extremely small clearance, there being a plurality of mandrels of different widths.
 19. The mandrel of claim 18 wherein top edges of said box-like structure are tapered to guide and direct product into said box-like structure.
 20. The mandrel of claim 18 and matched pairs of slots in opposite walls of said box-like structure to admit a pressing means for positioning product in said box-like structure prior to an insertion of said product into a carton.
 21. An automatic packaging machine comprising a conveyor for carrying a plurality of mandrels around a closed path, connector means for releasably coupling each of said mandrel to said conveyor, means for selectively operating said connector means to capture or release said mandrels, a plurality of magazines, means for storing different types of mandrels in individually associated ones of said magazines, robot means for removing mandrels from and replacing mandrels on said conveyors while said operating means releases and then captures said mandrels, said robot means placing removed mandrels in their individually associated magazine.
 22. The machine of claim 21 and conveyor means in each of said magazine for presenting mandrels to and receiving mandrels from said robot.
 23. The machine of claim 22 wherein said connector means comprises a stud dependent from each of said mandrels, a chamfered end and a locking groove on said stud, a slide having a keyhole therein, said stud fitting into a large end of said keyhole in a slide release position and said locking groove fitting into a small end of said keyhole in a slide capture position, and an air cylinder for moving said slide between said release and capture positions in synchronism with said robot removing and replacing of said mandrels. 